Sewing-machine looper



J. WHITELAW AND G. T. MAY, JR. SEWING MACHINE LOOP'ER. APPLICATION FILED APR. 17. I919.

Patented July 20, 1920.

4 SHEETS-SHEET l- 1. WHITELAW AND G. T. MAY, JR. SEWING MACHINE LOOPER.

APPLICATION FILED APR. I7, 1919. 1,347,313. P tented July 20, 1920.

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J. WHITELAW AND G T. MAY, 1R-

SEWlNG MACHINE LOOPER. I APPLICATION FILED APR. 17, 1919.

r .PatentedJu1y20, 1920. v

4 SHEETS-SHEET 3.

I i and Wzlauf Geozye TM J]; MWMM/MQQAL I. WHITELAW AND G. T. MAY, In. SEWING MACHINE LOOPER. APPLICATION FILED APR. 17. 1919.

Patbnted July 20, 1920.

4 SHEETSSHEET 4.

Infernal? and 72277881 JTR UNITED STATES PATENT OFFICE.

JAMES WHITELAW, OF ST. LOUIS, MISSOURI, AND GEORGE T. MAY, JR., OF CHICAGO,

' ILLINOIS.

SEWING-MACHINE LOOPER.

Specification of Letters Patent.

Patented July 20, 1920.

'Application filed April 17, 1919. Serial No. 290,763.

- the county of Cook and State of Illinois, re-

spectively, have invented certain new and useful Improvements in Sewing-Machine Loopers, of which the following is a specification.

Our invention relates to six-way loopers for chain-stitch sewing machines, more particularly for blind-stitch machines.

Its general object is to provide a simple, efficient looper mechanism capable-of operation at high speed and with greatest accuracy, and having excellent durability. The features of construction and combinations of parts constituting our invention are here inafter more fully described and set forth in the claims, andthe adva'ntaqes'thereof will be apparent from'the following description.

Inthe drawings wherein we have illustrated a single embodiment of our inven: tion, Figure 1 is a front View of the looper in assembled relation to'suitable parts of a blind-stitch sewing machine of the chainstitch type; Fig. 2. is an enlarged detail of a cam-operated lever element; Fig. 3 is an end elevation of the machine shown in Fig.

1; Fig. 4 is a vertical section on line 44 of Fig. 1; Fig. 5 is a detail of a driving connection; and Figs. 6, 7, 8 and 9-are fragmentary perspective views illustrating the cycle of operations of the looper in conjunction with the needle.

The general construction of the chain stitch machine illustrated is familiar to those skilled in the art as a well; known commercial device. It suffices here to generalize that the upper frame arm 10 carries a rigid presser foot 11 having a work opening 12 into which there works the plunger 13 suitably coordinated with the feed mech anism 14 and clamp element 15, all carried 'by the lower frame arm 16, the shaft for these work-handling and presenting parts receiving power throughconnections (not shown) from the main shaft 17 which extends through the upper arm and which also drives the needle bar 18, take-up 19, and looper mechanism 20. The needle bar 18 is pivoted on the upper arm with its axis paralleling the line of feed substantially in the vertical plane of the plunger, so that needle 18 Works transversely to the line of feed and, in this specific instance, at right angles thereto, directly over the plunger. The needle bar 18, in the particular construction shown, is driven by link 21 from crank pins 21 on a gear 22 the shaft 23 of which extends to the rear of the frame arm 10 to actuate the looper driving mechanism,

this gear 22 in turn being driven by a gear 24 on the main shaft 17. As thus far described, the machine involves nothing novel per se.

The novel looper structure specifically shown includes a bar having a rigid point 31, which bar is adjustably connected by a screw and slot arrangement 32 to the carrier 33, the bar 30 also carrying a pivoted spreader-arm member 34 with its point 34 movable relative to the main point 31, these connected parts constituting what we may term as a whole the movable unit of the looper. This looper unit is arranged in an upright position, presented approximately at right angles to the plane of the'presserfoot, and receives bodily movement up and down, fore and aft (transversely to the line of needle travel) and from side to side (or in the direction of needle travel) all without change of its angle with respect to the presser foot. To this end the carrier 33 of the unit receives this up and down and sidewise movement from parallel cranks of equal length, and the unit receives its fore and aft movement as a sliding action par allel to the crank axes.

In the specific construction shown the aforesaid cross shaft 23 for driving the needle bar carries a balanced disk 35 at the rear of the machine which, through a roller 36 operating in slot 37 drives the pivoted lever 38 which, through gear segment 39, in turn drives the pinion 40 on shaft 41 from which motion is communicated to shaft 42 by reversing pinion 43 and pinion 44. The shafts 41 and 42 disposed in parallelism and actuated alike and equally are the shafts of the parallel crank system. The shaft 41 preferably extends through the hub of the needle bar 18 and gives the latter its bearings, as shown in Fig. 4, thus locating the principal crank of the looper system coaxially with the needle bar. Shafts 41 and 42 have corresponding heads 45 and 46 from which extend the parallel crank pins 47 and 48, the former affording a long bearing for the cylindrical hub 49 of looper carriage 33 and the crank 48 receiving an open guidethe tail 63 of the spreader point striking:

the oscillations of the needle bar 18, the

crank shafts 47 and 48 will be equally oscillated in like directions, so that the movable looper unit will be transported bodily, and without change of its angular position, from side to side and up. and down. a

The hub of the looper carriage carries a laterally extending headed pin5l engaged by the slotted end 52 of an arm 53' that is vibrated fore and aft about a transverse pivot mounted in the frame. The lever arm 53 is preferably connected with this hub 59 by a pivot pin 60 transverse to the pin 54-, these loose connections at both top and bottom of the arm 53 insuring its adequate't'reed'om oi movement both laterally and verticallywith respect to the looper carriage, but maintaining an effective connection-whereby the cam operated lever may slide the .car riage fore and aft along its crank pin 4&7.

The precise structure of thelooper point or points may be varied, andthe particular spreadingpoint construction herein shown is not novel in this application. Sutfic'e it here to say that the spreader point Bet is closed by spring 62 upon the main point '31 when the point structure enters the loop, above the needle, as shown in Fig. 9, and that the two points are separated when, as shown in Fig. 7, the needle enters the loop the cam 64 fast on the head of the machine to effect this action. V v

In the cycle of operation as shown in Figs.

6 to 9, when the needle is sufiiciently re-' tracted to throw out the loop, the parallel crankpins stand at their rightward limit of oscillation, positioning the looper unit in fore and aft register with the loop, and when the parts arrive in this position cam 55 on the ma-i nshaft operates lever 53 to advance the closed looper points sovthat they pass through the loop above the needle; then during the retraction of the needle the-cam holds the looper carriage 33 forward while the crank pins oscillate to their leftward limit of movement, the loop thus being carried over the-work as shown inFig. 6 until the'tail ofthe spreading looper-arm strikes its cam 64', whereupon the looper points spread r as shown in Fig. 7 the main or rigid point'31 being depressed below the needle and the spreader point is held above the needle which meanwhile has passed its fully retractedposition and has begun its next pentration stroke. As the needle sweeps through the open loop thus positioned, the cam on the main shaft operates lever 53 to retract the looper unit, sliding it aft on its crank pin oscillation, completing the cycle.

respect to the plane of the workaft position or zone it remains while the parallel crank pins convey'the carrier sidewise'throughits idle excursion over the work to the rightward end of the path of crank It will be observed that by the parallellink effect, maintaining the looper unit always in the same angular positionin its. vertical and lateral movement, the crank pins travel through the full space that is traveled by the rigid looper point, and that all parts that would be subject to wear have large and adequate bearing surfaces, so that irregularities in looper movements due to initial or wear-engendered loosenesses of fit are minimized.

conducive to accuracy and low cost in pro duction. It will be understood, however, that in the broader aspects of our invention we donot limit it specifically to the illus trated construction shown as many changes in detail may be made without departure from the spirit of our invention andwithin the scope of the appended claims.

that we claim is: I l

1." The combination with a laterally reciprocating needleand means for presenting work thereto, of a looper comprising a movable unit having a' looper-point, and means for moving said unit through'a six-waypath Also it will .be noted that 7 all connections are of the simplest variety without changingthe angle ofsaid unitiwith.

2. In a sewingrnachine, the combination" with a' transverselyreciprocating needle and means forpresenting and feeding work with. respect thereto, of a-six:way looper comprising a movable unit having ..a looperpoint, parallel: equal crankmembers for moving said unit bodily, without change of its angular pos1t1on,up and down and transversely and means for-moving said looper- 7 point fore and aft acrossthepath of needle traverse. a f

3. In a sewingmachine, the combination with a jtransversely reciprocating needle and means for presenting and feeding work with respect thereto, of a six-way looper compris ing a movable unit having a looper-point, parallel equal crank members for fmoving said ,unit' bodily," without change of its angular position, up and down and transversely and cam actuated means for moving said looper-point fore and aft across the path ofneedle traverse. 7 7 -agln a sewing machine, the combination with a transversely.reciprocating needle and means for presentingandfeeding work with respect thereto,'of' a six-way, chain-stitch V looper comprising a movable unit having a point, parallel equal crank members for moving said unit bodily, without change of versely, and means for moving said'unit 7 its angular position, up and down and trans V i bodily, without change of angle, fore and aft, to pass said point across the line of needle traverse.

5. In a sewing machine, the combination with a transversely reciprocating needle and means for presenting andfeeding work with respect thereto, of a six-way, chain-stitch looper comprising a movable unit having a point, parallel equal crank members for moving said unit bodily, without change of its angular position, up and down and transversely, and means for sliding said unit bodily, without change of angle, fore and aft, to pass said point across the line of needle traverse.

6. In a sewing machine, a looper, providing a vertical looper bar having a point at its lower end, and means for bodily raising and lowering said looper bar, bodily displacing it laterally, and bodily displacing it fore and aft, said means maintaining unvaried the angular relation of thabar to the stationary portions of the machine.

7. In a looper mechanism for sewing machines, the combination with a frame of a looper unit having a point, a pair of parallel crank shafts carried by said frame having parallel similarly disposed pins of equal radius carrying and guiding said looper unit in an arcuate path, and means for sliding said looper unit fore and aft with respect to the frame. a

8. In a looper mechanism for sewing machines, the combination with a frame of a looper unit having a point, a pair of parallel crank shafts carried by said frame having parallel similarly disposed pins of equal radius carrying and guiding said looper unit in an arcuate path, and means for sliding said looper unit fore and aft with respect to the crank-shaft.

9, In a sewing machine looper mechanism, the combination of parallel cranks, means to operate them, a looper unit carried by and slidable on said cranks, and including a looper-point, and means for sliding said looper unit on said cranks.

10. In a sewing machine, a chain-stitch looper structure comprising a pair of parallel cranks, means to operate them, a looper carriage carried by and slidable on said cranks, a cam, a lever vibrated thereby, and lost motion connections between said lever and looper carriage, for sliding the carriage with respect to the cranks without restricting the displacement of the carriage by the cranks.

11. In a sewing machine looper, the combination of a looper carriage, a looper-point carried thereby, a crank pin carrying said carriage, a second crank pin engaging and guiding said carriage, means for oscillating said crank pins, and means for moving the carriage in a direction axial with respect to one of said crank pins.

JAMES WHITELAW. GEORGE T. MAY, JR. 

